Operating frequencies of semiconductor integrated circuits are steadily increasing. Meanwhile, power supply voltages supplied to semiconductor integrated circuits are decreasing every year in order to increase the operating frequencies of the semiconductor integrated circuits. Further, when the operating frequency of a semiconductor integrated circuit increases, problems such as noise and electromagnetic interference occur inside and outside of the semiconductor integrated circuit.
Patent Literature [PTL] 1 discloses a semiconductor device that suppresses noise and a leakage signal transmitted through a power line according to a change in the operating frequency or ambient circumstances by varying the capacitance value of a bypass capacitor provided so as to prevent interference to the semiconductor device having a plurality of circuit blocks. In the semiconductor device disclosed in Patent Literature 1, transistors that function as switches are added in order to switch the capacitance of the bypass capacitor.
Further, Patent Literature 2 discloses a technology that solves the issue of electromagnetic interference by providing a bypass capacitor in a semiconductor integrated circuit and having a transistor connected to the bypass capacitor operate as a switch. Therefore, the semiconductor integrated circuit disclosed in Patent Literature 2 has a transistor that functions as a switch added in order to switch the capacitance of a bypass capacitor as well.
Further, Patent Literature 3 discloses a technology that provides a capacitive element in a semiconductor integrated circuit and utilizes it as a bypass capacitor using a transistor.